US3970931A - Method of indicating and/or recording electrical quantities and indicating respectively recording apparatus embodying said method - Google Patents

Method of indicating and/or recording electrical quantities and indicating respectively recording apparatus embodying said method Download PDF

Info

Publication number
US3970931A
US3970931A US05/486,221 US48622174A US3970931A US 3970931 A US3970931 A US 3970931A US 48622174 A US48622174 A US 48622174A US 3970931 A US3970931 A US 3970931A
Authority
US
United States
Prior art keywords
frequency
voltage
comparator
input
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/486,221
Other languages
English (en)
Inventor
Ivan Novak
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
Original Assignee
US Philips Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3970931A publication Critical patent/US3970931A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K5/00—Manipulating of pulses not covered by one of the other main groups of this subclass
    • H03K5/00006—Changing the frequency
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R17/00—Measuring arrangements involving comparison with a reference value, e.g. bridge
    • G01R17/02—Arrangements in which the value to be measured is automatically compared with a reference value
    • G01R17/06—Automatic balancing arrangements
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/261—Amplifier which being suitable for instrumentation applications

Definitions

  • the invention relates to a method of indicating and/or recording electrical quantities and to an indicating -recording apparatus embodying said method.
  • An electrical quantity, after amplification, is applied, as the case may be via a measuring-point selector, to a servomotor whose shaft moves an indicating or recording element over a scale or a record carrier in such a way that the influence of a reference quantity which depends on the position of the indicating element is compensated.
  • an external resistance resistance thermometer
  • an internal resistance reference resistance
  • an external voltage thermoelement
  • an internal voltage reference voltage
  • An object of the invention is therefore to provide a method and an apparatus of the type mentioned in the preamble without the use of components which are subject to a wear and which adversely affect the reliability and the measuring accuracy.
  • the amplified electrical quantity is first converted into a first frequency which is proportional to its amplitude (desired frequency), after which said frequency is compared with a second frequency which depends on the instantaneous position of the indicating element (actual frequency).
  • the difference between the first (desired) frequency and the second (actual) frequency then controls a stepping motor which operates as a servomotor.
  • a recording apparatus which operates in accordance with said method comprises a voltage/frequency converter, a comparator circuit, a frequency limiter, a motor-control switch, a stepping motor whose shaft is connected to the pointer which is movable over the scale, as well as a position/frequency converter which is controlled by the pointer position, whose output frequency is supplied to the comparator circuit.
  • FIG. 1 shows a block diagram in explanation of the method according to the invention and of a suitable indicating or recording apparatus respectively
  • FIG. 2 shows the circuit diagram of an active filter
  • FIG. 3 shows the circuit of a measuring voltage chopper-amplifier
  • FIG. 4 shows the circuit diagram of a voltage/frequency converter
  • FIG. 5 represents the voltage variations in the circuit of FIG. 4,
  • FIG. 6 is a detailed diagram relating to the converter of FIG. 4,
  • FIG. 7 represents voltage variations in the circuit of FIG. 6,
  • FIG. 8 shows a circuit for quadrupling a frequency
  • FIG. 9 represents voltage variations in the circuit of FIG. 8,
  • FIG. 10 represents an addition of the actual frequency, the quadruple of the desired frequency and half the actual frequency
  • FIG. 11 represents an anticoincidence circuit
  • FIG. 12 represents a difference-forming circuit
  • FIG. 13 represents voltage variations in the circuit of FIG. 12,
  • FIG. 14 shows a graph of a frequency limiter
  • FIG. 15 is a diagram in explanation of linearization in a control circuit
  • FIG. 16 shows a circuit diagram of a linearized control circuit
  • FIG. 17 is a circuit diagram for the frequency limiter
  • FIG. 18 shows voltage variations in the circuit of FIG. 17,
  • FIG. 19 shows a circuit diagram of a power amplifier for a stepping motor.
  • the voltages obtained at one or more measuring points are passed via a measuring point selector 1 to the input of an active filter 2, which operates as a low-pass filter. Said filter rejects all disturbing frequencies above approximately 2 Hz.
  • the filter output is connected to the input of an amplifier 3, which amplifies the input voltage from approx. 5 mV to 0.5 V and subsequently transfers it to a first input of a voltage/frequency converter 4.
  • Said converter converts the input voltage of 0 . . . 0.5 V into a square-wave voltage with a frequency between 1.5 . . . 3.25 kHz, the period of the oscillation being linearly proportional to the input direct voltage.
  • Said square-wave voltage reaches a first input of a quadrupler circuit 5, at the output of which a frequency of 6 . . . 13kHz is available.
  • Said quadrupled frequency is now fed to a first input of a comparator circuit 7.
  • a second alternating voltage in the same frequency range of 6 . . . 13 kHz is fed to a second input of the comparator circuit 7.
  • a difference frequency of 0 . . . 7 kHz is now available, while a direction-dependent signal is available at a second output of the comparator circuit.
  • the difference frequency which may vary between 0 and 7 kHz, is applied to a first input of a frequency limiter 8.
  • Said limiter stage serves to limit the difference frequency of 0 . . . 7 kHz to 0 . . . 280 Hz, which frequency (i.e., 0 . . . 280 Hz) is simultaneously fed to a first input of a motor control switch 9 and a first input of a power amplifier 10.
  • a second input of the motor control switch 9 the direction-of-rotation signal S ⁇ f is applied.
  • the outputs of the control switch and the power amplifier in known manner, control a stepping motor 11, to the shaft of which an indicating element 13 is connected which can be moved over a scale 14.
  • a contactless position/frequency converter 12 which output frequency f ist , depending on the position of the indicating element, supplies a frequency between 12 . . . 26 kHz.
  • the latter frequency reaches a second input of the voltage/frequency converter 4, the quadrupler 5, the comparator 7 and the limiter 8, as well as an input of a frequency divider 6, in which said frequency is halved, i.e., reduced to a frequency within the range of 6 . . . 13 kHz. Said halved frequency is also fed to the comparator 7.
  • the inverting input of the complete amplifier should be provided with negative feedback.
  • the two MOS-FET's 26 and 30 are controlled by an astable multivibrator 32 whose frequency is approx. 700 Hz.
  • the direct voltage which is amplified by the amplifier 3 is converted into squarewave pulses in the voltage/frequency converter.
  • the period of these pulses is linearly proportional to the input voltage of the converter. The function is explained with reference to FIG. 4, while the variation in time is represented in FIG. 5.
  • a positive reference voltage U REF appears at the input of a voltage follower 37.
  • the reference voltage U REF which is reduced by a voltage divider 40, 41, 42 will appear at the minus input of a comparator 39.
  • the plus input of the comparator 39 is zero, its output will be negative.
  • the full reference voltage appears across a resistor 43, which with the capacitor 36 forms the integration time constant of the integrator 38.
  • the plus input of the integrator 38 is held at half the reference voltage by a voltage divider 44, 45. Consequently, a voltage difference equal to half the reference voltage is available between the two inputs of the integrator 38.
  • the integrator 38 During the integration process of the integrator 38 its output becomes more and more negative, which results in the positive voltage at the minus input of the comparator decreasing continuously. Once it is smaller than zero (i.e., negative), the comparator 39 changes over, its output becomes positive and the switch 35 is closed. As a result, the output of the voltage follower 37 becomes zero. The polarity of the voltage between the two inputs of the integrator 38 is then reversed. Moreover, only the negative output voltage of the integrator 38, which is attenuated by the resistors 40, 41, 42, acts at the minus input of the comparator 39. As only the polarity of the voltage between its inputs, but not the magnitude thereof changes, it now integrates at the same rate but in the other direction.
  • a squarewave voltage is obtained at the output of the comparator 39.
  • the period can be changed by changing the ratio of the resistors 40 and 41 to the resistor 42.
  • the reference voltage U REF required for conversion is provided by a zenerdiode 47 (FIG. 4).
  • the switches 35 and 48 are semiconductor switches. To the plus input of the comparator synchronisation pulses are applied whose magnitude does not influence the described function, but suffices to maintain the desired frequency of the converter in phase with the actual frequency of the position-transducer in the compensated condition.
  • the quadrupler 5 of FIG. 1 is represented more elaborately in FIG. 8.
  • the output frequency f soll of the voltage/frequenncy converter 4 is quadrupled, using the actual frequency f ist of the position-transducer as trigger frequency, and synchronized with said trigger frequency.
  • pulses will appear at the output of the quadrupler of FIG. 8 whose duration exactly equals the period of the transducer oscillation and whose number per unit of time is four times greater than the desired frequency, i.e., the output frequency of the voltage/frequency converter 4, which is available at the input of the quadrupler circuit 5.
  • Said circuit first of all consists of four J-K master-slave flip-flops 54, 54' and 55, 55'.
  • the logic state of the outputs (Q i , Q i ) at an arbitrary instant not only depends on the state of the inputs (J i , K i ), but also on the state of the memories at the same instant.
  • the device of FIG. 8 comprises four AND-gates F 1 , F 2 , F 3 and F 4 . The following equations are valid to said four AND-gates:
  • Each transition from "0" to "1" results in a pulse at the output F 1 after the next clock pulse arrives and in a pulse at the output F 3 after two more clock pulses. Both pulses have a duration equal to the clock period.
  • Each transition from "1" to "0" at the input J 1 results in a pulse at the output F 2 (FIG. 9) after the next clock pulse and in a pulse at the output F 4 after two more clock pulses.
  • the two pulses again have a duration equal to the clock period.
  • a pulse at the input which may be regarded as a dual change of state, results in four time-shifted pulses, which may be combined at one line by means of an OR-gate or by means of a NOR-gate.
  • the interval between the transitions is at least three clock periods, or in other words: the actual frequency should at least equal six times the desired frequency.
  • the pulses of the one transition coincide in time with those of the other transition, so that the input frequency is not quadrupled.
  • a delay element has been included between the preamplifier and the voltage/frequency converter, which element consists of a resistance 50 and a capacitance 51, whose time constant is proportioned so as to prevent a too rapid change of the converter frequency f soll .
  • the frequency of the voltage/frequency converter 4 (FIG. 1) is quadrupled, i.e., transposed to the frequency range of approx 6 . . . 13 kHz, the pulse duration being independent of the frequency and always corresponding to the period of the actual frequency.
  • the actual frequency is also transposed to the same range of 6 . . . 13 kHz. Both frequencies are now in the same frequency range; they are synchronized with each other and have the same pulse lengths, as is shown in FIG. 10.
  • stage 7 The difference between the two frequencies is determined in the stage 7 (FIG. 1).
  • Said stage first of all comprises an anticoincidence stage (FIG. 11) followed by a counting stage in accordance with FIG. 12, in which the difference frequency is produced.
  • the pulses at the lines A B or A B always have a length of only one clock period T ist . This means that they are always spaced at least two clock periods apart. However, a pulse at one line may already be followed by a pulse at the other line in the next clock period (FIG. 13).
  • the J-K flip-flop 56 is triggered by the actual frequency.
  • each further pulse at a line A B is transferred, but only when the line A B has been continuously 0.
  • the upper AND-gate 57 supplies the difference frequency when half the actual frequency is greater than four times the desired frequency
  • the lower AND-gate 58 supplies the difference frequency when the actual frequency is smaller than eight times the desired frequency.
  • the two AND-gates 57 and 58 remain at 0 because all pulses cancel each other either in the anticoincidence circuit or in the counter.
  • NOR-gate 59 is included, which is followed by a second NOR-gate 60 which is connected as an inverter, at whose output the difference frequency ⁇ f is available.
  • the difference frequency ⁇ f of 0 . . . 7 kHz is available.
  • the prevailing difference frequency should be limited to a maximum of said value and preferably to a value which is slightly lower.
  • said maximum frequency is 280 Hz, as is shown in FIG. 14.
  • the difference frequency ⁇ f is plotted on the horizontal axis and the limited difference frequency ⁇ fb on the vertical axis, the latter frequency being 280 Hz.
  • the constant K 1 characterizes the U e /T soll converter, the constant K 3 the inductive transducer and the factor K 2 /p allows for the integrating behaviour of the stepping motor.
  • the starting process is divided into two successive parts, i.e., a linear first part and an exponential second part. This ensures that the stepping motor initially operates at its maximum permissible speed of approx. 280 steps per second.
  • the stepping motor then operates with said constant speed until the difference frequency ⁇ f owing to the mutual approach of the actual position and the desired position decreases below the value of 280 Hz. This happens at a specific instant before the final value is reached and from that instant on the actual position and the desired position approach each other exponentially with decreasing speed. As soon as the two positions correspond, the difference circuit supplies no more pulses and the stepping motor and the indicating element remain stationary.
  • the difference frequency ⁇ f is applied to the input K of a J-K flip-flop 63, which is simultaneously triggered by the actual frequency f ist .
  • the other input J is permanently at 1-potential (+5V). With this flip-flop each pulse, which each time has a length of only one clock period, appears at the output Q with a delay of one clock period. When at the output Q the 1 potential appears, the output Q simultaneously becomes 0, as is shown in FIG. 18.
  • Said potential variation from 1 to 0 at the output Q results in a following monostable 64 being triggered via its inputs 65, while its third input 66 is maintained at the 1 potential by the output 67 (M 2 ) of a second monostable 68.
  • a pulse appears whose duration has been adjusted by resistor 70 and a capacitor 71 to half the period of the maximum stepping frequency of 280 Hz.
  • the falling edge of said pulse triggers the second monostable 68 via its parallel connected inputs, while its third input is permanently at the 1 potential (+5V).
  • a pulse appears at the output 72, (M 2 ) of the second monostable 68, whose duration has also been adjusted to half the period of 280 Hz by a resistor 73 and a capacitor 74.
  • the flip-flop stores the first pulse that reaches its input k during the period of the pulse at the output 72 (M 2 ) of the second monostable 68.
  • the first monostable 64 is immediately retriggered owing to the simultaneous change from 0 to 1 at the input 66 of the said monostable, after which the entire process is repeated.
  • pulses of a repetition frequency below 280Hz pass the circuit without frequency variation.
  • all higher frequencies are limited to 280 Hz, for owing to the storage of the incoming pulses in the flip-flop 63 the one monostable immediately triggers the other.
  • this can happen only 280 times per second.
  • a stepping motor as employed in the present circuit, is a component which in conjunction with an electrical or electronic control switch provides a direct conversion of digital electrical information (pulses) into defined mechanical angular steps. Upon each pulse applied to the control switch, the motor switch is rotated through an angle which is specific for the relevant motor.
  • the applied position/frequency converter is of a design known per se, so that it need not be further described.
  • circuit arrangement is merely an embodiment of an apparatus which operates in accordance with the novel method. It is obvious that different frequencies may be used as basic frequencies.

Landscapes

  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Control Of Stepping Motors (AREA)
  • Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
  • Measurement Of Current Or Voltage (AREA)
US05/486,221 1973-06-30 1974-07-05 Method of indicating and/or recording electrical quantities and indicating respectively recording apparatus embodying said method Expired - Lifetime US3970931A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DT2333413 1973-06-30
DE2333413A DE2333413C2 (de) 1973-06-30 1973-06-30 Verfahren zur Anzeige und/oder Registrierung elektrischer Größen und Anzeige- bzw. Registriergerät unter Anwendung dieses Verfahrens

Publications (1)

Publication Number Publication Date
US3970931A true US3970931A (en) 1976-07-20

Family

ID=5885620

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/486,221 Expired - Lifetime US3970931A (en) 1973-06-30 1974-07-05 Method of indicating and/or recording electrical quantities and indicating respectively recording apparatus embodying said method

Country Status (8)

Country Link
US (1) US3970931A (it)
JP (1) JPS5526430B2 (it)
DE (1) DE2333413C2 (it)
FR (1) FR2235357B1 (it)
GB (1) GB1474788A (it)
IT (1) IT1016215B (it)
NL (1) NL7408581A (it)
SE (1) SE400647B (it)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4083052A (en) * 1976-06-16 1978-04-04 Sangamo Electric Company Electronic tachograph
US5367241A (en) * 1992-07-09 1994-11-22 Samsung Electronics Co., Ltd. Rotation speed detecting apparatus for a motor having an encoder
US5563980A (en) * 1994-12-14 1996-10-08 Industrial Technology Research Institute Brushless DC motor speed controller

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5540426U (it) * 1978-09-01 1980-03-15
DE3234883A1 (de) * 1982-09-21 1984-03-22 Lehrmittelbau Prof.Dr.Maey GmbH, 5300 Bonn Linienschreiber
JPS5965715A (ja) * 1982-10-07 1984-04-14 Yokogawa Hokushin Electric Corp サ−ボ機構
US5121008A (en) * 1990-11-29 1992-06-09 Talmadge Paul C Circuit for generating or demodulating a square wave and other wave forms
US5287748A (en) * 1992-05-01 1994-02-22 Pitney Bowes Inc. Method and apparatus for changing the sensitivity of a transducer

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3094875A (en) * 1961-09-29 1963-06-25 Phillips Petroleum Co Low level voltage to frequency converter
US3228025A (en) * 1961-02-02 1966-01-04 Barton Instr Corp Analog to digital converter
US3418547A (en) * 1965-03-22 1968-12-24 Gen Signal Corp Step-servocontroller
US3619757A (en) * 1969-04-22 1971-11-09 Bendix Corp Variable speed closed loop digital servosystem

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1356277A (fr) * 1962-12-29 1964-03-27 Dispositif de mesure du volume du liquide contenu dans une cuve
US3408568A (en) * 1963-06-24 1968-10-29 United Systems Corp Servo-balancing voltmeter employing an overvoltage protected chopper and a d.c. damped servo-motor
US3555418A (en) * 1967-09-29 1971-01-12 Phillips Petroleum Co Oscillator having voltage sensitive capacitors therein and calibration circuit means
JPS514218A (ja) * 1975-06-02 1976-01-14 Toyo Jozo Kk Monasukasushikisonoseizoho

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3228025A (en) * 1961-02-02 1966-01-04 Barton Instr Corp Analog to digital converter
US3094875A (en) * 1961-09-29 1963-06-25 Phillips Petroleum Co Low level voltage to frequency converter
US3418547A (en) * 1965-03-22 1968-12-24 Gen Signal Corp Step-servocontroller
US3619757A (en) * 1969-04-22 1971-11-09 Bendix Corp Variable speed closed loop digital servosystem

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4083052A (en) * 1976-06-16 1978-04-04 Sangamo Electric Company Electronic tachograph
US5367241A (en) * 1992-07-09 1994-11-22 Samsung Electronics Co., Ltd. Rotation speed detecting apparatus for a motor having an encoder
US5563980A (en) * 1994-12-14 1996-10-08 Industrial Technology Research Institute Brushless DC motor speed controller

Also Published As

Publication number Publication date
IT1016215B (it) 1977-05-30
DE2333413C2 (de) 1975-10-02
SE400647B (sv) 1978-04-03
JPS5526430B2 (it) 1980-07-12
NL7408581A (nl) 1975-01-02
SE7408457L (it) 1975-01-02
FR2235357A1 (it) 1975-01-24
JPS5089073A (it) 1975-07-17
GB1474788A (en) 1977-05-25
FR2235357B1 (it) 1978-02-17
DE2333413B1 (de) 1975-02-13

Similar Documents

Publication Publication Date Title
US3361949A (en) Motor control servo system
US4228396A (en) Electronic tachometer and combined brushless motor commutation and tachometer system
USRE23121E (en) Antihunting electrical measuring and control apparatus
US3110853A (en) Electrical control apparatus
JPS6132894B2 (it)
EP0077403B1 (en) Speed detecting device
US3235800A (en) System for measuring frequency by comparing unknown to reference and determining therate of change of phase
US3612975A (en) Electronic data-processing apparatus
US3008075A (en) Phase stabilizing circuit
US3668494A (en) Constant displacement stopping control
US4034276A (en) Digital signal processor for servo velocity control
US3854081A (en) Servo error signal generator for numerical control systems
DE68910858T2 (de) Verfahren zur Regelung der Spurhaltung bei einem Magnetband mit Videospur und Steuerspur.
US3603979A (en) Digital system including temperature compensating means
US3619757A (en) Variable speed closed loop digital servosystem
US3820024A (en) Electronic velocimeter
US3665282A (en) Scan control system
US4042868A (en) Stepper motor control apparatus
US3430227A (en) Drift compensation circuit for analog-to-digital converter
US3486090A (en) Remote control and indicator system with control maintained through a remote variable frequency source
US3809452A (en) System for controlling number of revolutions of the tape drive in a tape recording and replaying apparatus
US3404857A (en) Signal generator for control systems
US2975411A (en) Analog to digital converter apparatus
US3767991A (en) Microelectronic three-wire synchronizer
US3457480A (en) Tape controlled servo for a machine tool including a unique pulse width modulated motor control